By: mobal , 9:44 PM GMT en Abril 29, 2012
The Search for the 100-MPG Car
By Dexter Wright
Since the 1970s, it has been the quest of the United States to achieve energy-independence. To that end, President Jimmy Carter established the Department of Energy so that the federal government could write checks to companies like Solyndra -- companies that generate not power, but rather questions. More recently, the grail quest has inspired the EPA and the Department of Transportation (DoT) to wave a magic wand and mandate corporate average fuel economy standards (CAFÉ standards) for vehicles at 54.5 miles per gallon by 2025 -- a mileage standard that not even a Harley-Davison motorcycle can achieve.
The plan as unveiled by the EPA and DoT is to have 11 million electric cars on the road by 2025. The thought is that with 11 million "zero emission" cars on the road, the average efficiency will rise. It probably comes as no surprise that there are major problems with this government pie-in-the-sky plan.
Let's start with the facts. Recently the EPA was caught trying to suppress a report that the U.S. power grid might not be able to withstand the new "pollution" standards without triggering rolling blackouts. What the report does not mention is that adding a major demand of 11 million new electrical appliances, called electric cars, will very likely collapse the grid. But not to worry: no one wants to buy the "premier" electric vehicle, the Chevy Volt, since it is prone to spontaneous combustion. But even before the disturbing fire hazard was discovered, the New York Times accurately guessed that "the Volt will likely be too expensive to be commercially successful in the short term[.]"
So in response to this failure the Obama administration has decided not to back away from the 2025 fleet average of 54.5 MPG. This sort of centralized economic planning does not have a successful track record. Other than the internet, there is not one product that the federal government has created that has been successful.
But why does the 100-MPG car seem so out of reach? Others areas of transportation have had major advancements. In the 1930s, the railroads more than doubled their efficiency by switching from steam to diesel electric locomotives. In the 1950s, airlines quickly switched from reciprocating propeller engines to turbo jet engines to achieve a more-than-threefold increase in efficiency. But the automobile has yet to achieve any significant improvement in efficiency in over a hundred years.
In 1908, the Model T Ford rolled off the assembly line with a four-cylinder engine capable of achieving 25 MPG. Today, the production-line Toyota Corolla can get 26 MPG. Yes, the Corolla weighs a bit more and burns the fuel cleaner that the 1908 Model T, but the fuel efficiency of the modern Toyota is negligibly improved.
The answer to the question why there are no great leaps forward in automobile efficiencies is simple. With both railroads and aviation, the improvements in efficiency were achieved by throwing out the older engines and replacing them with a new one of a completely different design. The plain fact of the matter is that the internal combustion engine has gone about as far in efficiency improvements as it can because of the way it functions.
The function of the internal combustion (IC) engine depends on the explosion of gasses to move the pistons in the cylinders back and forth. This explosion represents only 14% of the available energy in a gallon of gasoline. That is to say that only 14% of the available energy in a gallon of gasoline is converted into shaft horsepower; the rest is thrown away as waste heat through the tailpipe and radiator. So the majority of the available energy is simply wasted. There is, however, an engine that was developed that uses the heat from burning gasoline rather than its explosive energy.
In 1986, when gas was selling at the pump for a dollar, NASA decided it would begin a project to improve the fuel efficiency of the automobile. This project was known as the Stirling Automotive Engine Development Program.
It seems that one of the bright rocket scientists decided to apply the properties of an engine under consideration for spacecraft use to the automobile; the result was a Stirling Cycle engine. As an external combustion engine, it is fundamentally different from the IC engine. This type of engine configuration burns fuel in a burn chamber to heat a motive gas, not unlike a fire grate, which heats the steam in the boiler of a steam engine. The result is that this engine uses the portion of a gallon of gasoline that has the most energy: the heat generated from burning the gasoline.
NASA was able to achieve 58 MPG by replacing the IC engine in the Chevy Celebrity with a Stirling engine with a 38% overall maximum efficiency; more than twice that of an IC engine. Although this project had impressive results, it fell short of the Holy Grail of 100 MPG. As an example of typical government behavior, the successful program was therefore shelved with no further development.
Fast-forward to the 21st century and look at one of the attempts to achieve the 100-MPG car. The Automotive X Prize originally solicited competitors to design and build a production-line vehicle that could achieve 100 MPG. The winners were essentially motorcycles with composite frames, all of which used the IC engine.
However, a search of the Patent and Trademark Office does hold a glimmer of hope that we will not all be riding a motorcycle with a side car in 2025. The Holy Grail of 100 MPG seems to have been found in Texas. The approved patent, for a Stirling Hybrid Electric Automobile, has seemingly doubled the efficiency that NASA achieved by changing the design. The inventor, Mr. McDowell, has introduced a heat exchanger that converts the hot exhaust gas directly into electrical current, which is fed back into the hybrid electrical system. The design is much like that of the Toyota Prius, except that there is a Stirling engine and not an IC engine. This invention proves once again that the private sector is better at this Grail Quest than government.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.
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